This invention relates to a magnetic recording and/or reproduction method and a magnetic head assembly and a magnetic recording and/or reproduction apparatus for practicing this method, and particularly to a magnetic recording and/or reproduction method, a magnetic head assembly and a magnetic recording and/or reproduction apparatus suitable for a video tape recorder or a magnetic disc apparatus.
In magnetic recording and reproduction apparatuses such as for example video tape recorders (VTRs), because in order to raise the recording density the distance (the guard band width) between mutually adjacent recording tracks (hereinafter simply called `tracks`) is almost zero or is made extremely small, there has been the problem that crosstalk from adjacent tracks tends to occur during recording and reproduction.
To overcome this problem, in common VTRs, crosstalk is reduced by the adoption of so-called azimuth recording wherein the inclinations of magnetic gaps of magnetic heads recording mutually adjacent tracks are made different. In recent years, to improve the picture quality of VTRs and the like, high quality television signal recording and digital recording wherein signals are digitized before being recorded have been advanced, higher magnetic recording densities have been being advanced together with this, and track widths have been being made smaller. Because of this, there is a limit to the extent to which crosstalk can be prevented by relying on azimuth recording alone.
Along with magnetic materials of high coercive force being used as high density magnetic recording and high frequency magnetic recording progress, so-called metal-in-gap heads wherein a metallic magnetic film is disposed in the magnetic gap in order to increase the recording capability of the magnetic head are starting to be used as magnetic heads used for recording and reproduction. Also, to handle the adoption of high recording and reproduction signal frequencies magnetic heads wherein the magnetic paths are constituted by metallic magnetic films only and the magnetic films are separated by insulating films of oxide or the like to reduce eddy current losses in the metallic magnetic films are starting to be used.
However, magnetic heads of a construction such that the insulating films and the magnetic gap are mutually parallel are not preferable because the insulating films form false magnetic gaps. To avoid this, magnetic heads of the kind shown in FIG. 1 wherein the surfaces of magnetic films 43 and the surfaces of insulating films 44 are substantially aligned with the magnetic head travel direction (i.e. the track direction) and magnetic heads of the kind shown in FIG. 2 wherein the surfaces of magnetic films 53 and the surfaces of insulating films 54 are inclined with respect to the track direction have been proposed. In FIG. 1 and FIG. 2, 42 and 52 are magnetic gaps, 47 and 57 are non-magnetic base bodies and 56 is glass.
Along with increases in the recording density of magnetic recording of VTRs and the like, and particularly increases in the track density, magnetic recording apparatuses have been becoming more subject to influences from adjacent tracks such as crosstalk. In this connection, studies aimed at reducing influences from adjacent tracks by methods such as increasing the azimuth angle of the magnetic heads have been being carried out.
By increasing the azimuth angle it is possible to reduce the size of signals from adjacent tracks with respect to the signal being reproduced from the present track, but unwanted signals reproduced other than through the magnetic gap are not reduced so much and when the track width is made small to increase the recording density the influence of these unwanted signals becomes relatively large. Especially in magnetic heads of the kind shown in FIG. 2 wherein the magnetic films are inclined with respect to the track direction, because the magnetic films always make contact with the adjacent tracks, influences from the adjacent tracks are greater than in the magnetic head shown in FIG. 1. However, magnetic heads of the structure shown in FIG. 1, because it is necessary to cut the non-magnetic base body and the magnetic films, which have greatly different hardnesses, in the same step, are not easy to manufacture and are unsuited to mass production.